Once a player reaches SR-50, he must choose a Specialization in order to continue ranking up. Each Specialization accounts for 10 additional SR ranks. After all 8 Specializations have been completed, the player will have reached the maximum rank of SR-130.

When a player chooses a Specialization, his rank immediately increases (for example, from SR-50 to SR-51).

Each Specialization rank unlocks a specific customization item as follows:

“Spartan optimization for long range target tracking [trans-continent and off-world]. particularly in scenarios where conventional tracking has failed or such a substantial time has passed that the trail has gone cold.”

Competitive Skill Rank (CSR) measures a player's skill in a playlist on a scale of 1 to 50. Players start at 1 and rank up or down depending on their performance and rank relative to other players in the match.[1] It was implemented on April 8, 2013, and is only visible on Halo Waypoint.

CSR is always a game behind. That means that after every game, CSR is updated with the effects from the game before it.[1]

Players who join a game in progress are treated as if they played the entire match.[1]

Although 343 Industries officially stated that leaving a match before it's finished counts the player as having lost in team-based CSR playlists and being the lowest-scoring player in individual CSR playlists,[1] quitting a match does not affect CSR at all.[2][3]

Players can view the CSRs of the players they played against by going to their Game History in their Halo 4 Stats on Halo Waypoint.

Team-based CSR judges players based strictly on whether they won or lost regardless of individual performance such as kills or score.[1] Players will rank up if they consistently win against teams of players who are ranked the same as or higher than they are.

Playlists that use team-based CSR typically focus on teamwork, such as Team Slayer, Capture the Flag, and Proving Ground.

Individual CSR judges players based strictly on their score regardless of whether their team won or lost.[1] Players will rank up if they consistently score higher than players who are ranked the same as or higher than they are.

Playlists that use individual CSR typically focus on individual skill, such as Rumble Pit, Team Snipers, and Big Team Battle.

At Halo 4's launch, only the Wetwork and Operator Specializations were available. Pioneer and Pathfinder were made available on 1/21/2013, Engineer and Stalker were made available on 1/28/2013, and Rogue and Tracker were made available on 2/4/2013.[4] Players who purchased the Halo 4 Limited Edition or played Halo 4 while connected to Xbox Live by November 20, 2012, had access to all eight at launch.[5]